PSLEIn the figure, ZABC is a parallelogram. ZXC and XBY are straight lines. ∠YBC = 149°, ∠ZCB = 47° and ∠ZBX = 20°.
- Find ∠ABY.
- Find ∠AZB.
(a)
∠ABC
= 180° - 47°
= 133° (Interior angles)
∠ABY
= 360° - 149° - 133°
= 78° (Angles at a point)
(b)
∠CBX
= 180° - 149°
= 31°(Angles on a straight line)
∠AZB
= ∠ZBC
= 31° + 20°
= 51° (Alternate angles)
Answer(s): (a) 78°; (b) 51°